Process Concept

A question that arises in discussing operating systems involves what to call all
the CPU activities. A batch system executes jobs, whereas a time-shared system
has user programs, or tasks. Even on a single-user system such as Microsoft
Windows, a user may be able to run several programs at one time: a word
processor, a web browser, and an e-mail package. Even if the user can execute only one program at a time, the operating system may need to suppoft its
own internal programmed activities, such as memory management. In many
respects, all these activities are similar, so we call all of them processes.
The terms job and process are used almost interchangeably in this text.
Although we personally prefer the term process, much of operating-system
theory and terminology was developed during a time when the major activity
of operating systems was job processing. It would be misleading to avoid
the use of commonly accepted terms that include the word job (such as job
scheduling) simply because process has superseded job.